First, a primordial cosmological magnetic field has been
proposed, althought very
small in strength to comply with its non-detection, and thus it
may be unimportant when
compared to the turbulent kinetic energy in clusters. It is by no
means certain that extremely weak, random, primordial seed magnetic fields
< 10-10 Gauss are sufficient to
account for observed magnetic fields in clusters of galaxies and
in galaxies (e.g.,
Kim et al. 1996).

A second potential seed field would be coming from the
relics of extended double
radio sources or radio trails in clusters, being shredded by the
turbulent wakes of passing
galaxies. However, not all clusters have one or more extended
radio doubles or radio trails,
and many clusters have none. This seed field may be limited in
its application.

A third potential seed field model proposed uses the ejected
magnetic field and gas
from the interstellar medium of the galaxies in the cluster,
which could diffuse out of the
galaxies or else be blown out of the galaxies by stellar winds,
supernovae, galactic fountains, tidal strippings, etc, at a rate of
~ 1M per
galaxy per year (e.g.,
Goldschmidt & Rephaeli
1993;
De Young 1992).
This process can be widely distributed and it has the advantage of
transfering kinetic energy from the extracting process to the
intracluster medium.